全文获取类型
收费全文 | 26641篇 |
免费 | 2049篇 |
国内免费 | 911篇 |
专业分类
电工技术 | 1452篇 |
综合类 | 1562篇 |
化学工业 | 1436篇 |
金属工艺 | 2576篇 |
机械仪表 | 1858篇 |
建筑科学 | 1816篇 |
矿业工程 | 475篇 |
能源动力 | 375篇 |
轻工业 | 5415篇 |
水利工程 | 232篇 |
石油天然气 | 1866篇 |
武器工业 | 263篇 |
无线电 | 1998篇 |
一般工业技术 | 3074篇 |
冶金工业 | 825篇 |
原子能技术 | 157篇 |
自动化技术 | 4221篇 |
出版年
2024年 | 90篇 |
2023年 | 310篇 |
2022年 | 486篇 |
2021年 | 705篇 |
2020年 | 736篇 |
2019年 | 645篇 |
2018年 | 600篇 |
2017年 | 790篇 |
2016年 | 865篇 |
2015年 | 1085篇 |
2014年 | 1505篇 |
2013年 | 1461篇 |
2012年 | 1830篇 |
2011年 | 1954篇 |
2010年 | 1593篇 |
2009年 | 1551篇 |
2008年 | 1521篇 |
2007年 | 1689篇 |
2006年 | 1488篇 |
2005年 | 1350篇 |
2004年 | 1126篇 |
2003年 | 1010篇 |
2002年 | 887篇 |
2001年 | 736篇 |
2000年 | 592篇 |
1999年 | 497篇 |
1998年 | 430篇 |
1997年 | 324篇 |
1996年 | 310篇 |
1995年 | 254篇 |
1994年 | 199篇 |
1993年 | 167篇 |
1992年 | 168篇 |
1991年 | 115篇 |
1990年 | 93篇 |
1989年 | 67篇 |
1988年 | 43篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1985年 | 31篇 |
1984年 | 26篇 |
1983年 | 31篇 |
1982年 | 32篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1965年 | 19篇 |
1964年 | 14篇 |
1962年 | 11篇 |
1959年 | 8篇 |
1955年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
As we approach 100 nm technology the interconnect issues are becoming one of the main concerns in the testing of gigahertz system-on-chips. Voltage distortion (noise) and delay violations (skew) contribute to the signal integrity loss and ultimately functional error, performance degradation and reliability problems. In this paper, we first define a model for integrity faults on the high-speed interconnects. Then, we present a BIST-based test methodology that includes two special cells to detect and measure noise and skew occurring on the interconnects of the gigahertz system-on-chips. Using an inexpensive test architecture the integrity information accumulated by these special cells can be scanned out for final test and reliability analysis. 相似文献
54.
F.D. Lydon 《Construction and Building Materials》1993,7(4):213-220
A modified version of a test, originally proposed by BRE (UK), was used to assess relative permeability to nitrogen gas of concretes cured in various ways. Three simple parameters from test plots clearly showed the effects of duration of water curing, followed by drying to constant mass at 50°C; test specimen moisture content was dominant and drying at 105°C reduced differences between concretes of very different quality. Convincing evidence was not found of differences between upper and lower ‘halves’ of cylinders nor between cast and cored ones. 相似文献
55.
衍射法细丝直径的精密测量 总被引:4,自引:2,他引:2
分析了激光衍射法测量细丝直径技术中影响精度的几个主要因素,研究了一种微弱衍射条纹的精密处理及识别技术,有效地提高了测量精度,实测结果表明,文中讨论的技术能在10 ̄50μm的范围内实现正负0.1μm的重复精度,分辨力优于0.01μm。 相似文献
56.
Test Case Generation as an AI Planning Problem 总被引:6,自引:0,他引:6
Adele E. Howe Anneliese von Mayrhauser Richard T. Mraz 《Automated Software Engineering》1997,4(1):77-106
While Artificial Intelligence techniques have been applied to a variety of software engineering applications, the area of automated software testing remains largely unexplored. Yet, test cases for certain types of systems (e.g., those with command language interfaces and transaction based systems) are similar to plans. We have exploited this similarity by constructing an automated test case generator with an AI planning system at its core. We compared the functionality and output of two systems, one based on Software Engineering techniques and the other on planning, for a real application: the StorageTek robot tape library command language. From this, we showed that AI planning is a viable technique for test case generation and that the two approaches are complementary in their capabilities. 相似文献
57.
埋地管道涂层检测技术现状 总被引:3,自引:0,他引:3
李继华 《石油化工腐蚀与防护》1998,15(4):4-6,52
文章对各种埋地管道涂层检测技术进行了综述,并指出了各种技术的优缺点及应用前景. 相似文献
58.
提出了一种用于检测在役车辆车轴产生疲劳裂纹的超声波方法,设计了中心孔探头与斜角探头一起,完成了对车辆车轴的关键区域探伤。 相似文献
59.
在小子样情况下 ,利用系统和分系统试验数据对导弹的飞行可靠性指标进行评定 ,从数学上说是系统可靠性综合问题 .运用MML SR方法对新型号地地战术导弹的飞行可靠性指标进行评定 ,避免了MML方法在遇到无失败单元时不适用的缺陷 ,在利用地面试验信息方面有其明显优势 ;运用Bayes方法对改进型导弹的飞行可靠性指标进行评定 ,将不同试验阶段的多源试验信息作为验前信息 ,扩大了信息量 .最后 ,对两种方法在工程应用上遇到的问题进行了讨论 ,并给出了解决方法 . 相似文献
60.
ABSTRACT: :
Soybeans ( Glycine max ) were soaked and ground to obtain soymilk. The soymilk was cooked in an open tank and held at 85 to 90 deg;C. Yuba films were picked up in 20 min intervals and dried for 20 min. Yuba films were soaked in chicken-flavor solutions (25% and 35%), and baking soda (BS) solutions (0%, 1%, 2%, and 3% BS), and cooked at 100 °C for 30 min, 60 min, and 90 min. TIA decreased (p < 0.05) with the increase of heating time and BS concentration. In vitro protein digestibility (IVPD) decreased with heating time and BS concentration (p < 0.05). Sensory characteristics were affected by flavor concentration. By using 0% BS, 25% of the chicken flavor concentration, and a short heating time method, meat-like products with low TIA, high IVPD, and good sensory characteristics were obtained. 相似文献
Soybeans ( Glycine max ) were soaked and ground to obtain soymilk. The soymilk was cooked in an open tank and held at 85 to 90 deg;C. Yuba films were picked up in 20 min intervals and dried for 20 min. Yuba films were soaked in chicken-flavor solutions (25% and 35%), and baking soda (BS) solutions (0%, 1%, 2%, and 3% BS), and cooked at 100 °C for 30 min, 60 min, and 90 min. TIA decreased (p < 0.05) with the increase of heating time and BS concentration. In vitro protein digestibility (IVPD) decreased with heating time and BS concentration (p < 0.05). Sensory characteristics were affected by flavor concentration. By using 0% BS, 25% of the chicken flavor concentration, and a short heating time method, meat-like products with low TIA, high IVPD, and good sensory characteristics were obtained. 相似文献